Thanks for the vote of confidence. Made in Painesville OH, too. $165 for a M-121 muffler, would probably fit most MCI's from the same kind of time period as mine. Smaller than the OEM muffler by a lot, same height at around 10" but 15" wide instead of over 20" for the MCI, around the same length at 26" vs about 28" for the MCI. Input on the MCI is 5" but the output was weird at 4.25" from memory. I had to make a custom piece for the output when I built my exhaust three years ago. I am going to put a 5" chrome tip on this one, just like the kids with the rattle cars have

M-121 is the same number, and same muffler I'm using in my bus, but from Donaldson. I guarantee they are selling the Donaldson muffler. Good muffler, turbo rated, and puts out a nice tone. Good Luck, TomC